Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-10-15
2001-05-01
Crispino, Richard (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S062200, C156S072000, C156S240000, C156S241000, C156S247000, C156S289000, C156S244190, C427S146000, C427S147000, C427S148000, C427S200000, C427S206000, C427S208000, C428S090000, C428S914000, C008S471000, C008S478000
Reexamination Certificate
active
06224707
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an automatic, continuous method for printing multicolor-designs on a thermoadhesive or high-frequency (HF) weldable flocked film or substrate, to the film obtained by this printing method, as well to a method of application of this film onto a substrate to be decorated, such as a fabric, and consequently to the substrate printed according to this method.
BACKGROUND OF THE INVENTION
Printing by transfer-sublimation, i. e. by means of sublimable dyes, is already known, and it can be described as the printing, in a first step, of designs on a paper substrate by using inks constituted by sublimable dyes, capable of vaporizing when reaching a certain temperature and of fixing themselves permanently on certain synthetic fibers, whereas different methods can be used for printing the paper substrate, for instance offset, flexography- or heliography-printing, or flat-bed or rotary screen-printing. Then, in a second step, the pre-printed designs of sublimable dyes—as applied on the paper substrate—are transferred by contact under predetermined pressure and temperature between the printed paper and the fabric to be decorated.
This method of transfer-sublimation is currently used for printing on synthetic fabrics as well as on the surface of flocked fabrics which are commonly used for upholstery or automobile decoration.
However, this method has never been used for the printing of thermoadhesive or high-frequency-weldable flocked films, because the thermal sensitivity of such films makes it very difficult to print by transfer-sublimation, as this operation must be carried out at a minimum temperature of 180° C. (350° F.), which is a temperature that those films are unable to stand.
Furthermore, thermoadhesive or high-frequency-weldable films are commonly flocked with fibers made of rayon-viscose, which fibers cannot be printed satisfactorily by the existing method of transfer-sublimation.
Thermoadhesive or weldable flocked films are commonly used for the decoration of garments, fabric products and accessories, and more generally of all substrates suitable for decoration by means of heat-application or high-frequency (HF) welding.
Those thermoadhesive or weldable films are usually flocked with fibers which are dyed before flocking, which leads to one-color flocked surfaces in which patterns like numbers, letters or logos are cut out before being applied onto the substrate to be decorated.
For printing multicolored designs on a thermoadhesive or HF-weldable film, usually a screen-printing of a white-colored flocked film is carried out. Generally, white flock-fibers made of rayon-viscose are used. The thermoadhesive or HF-weldable flocked film which is screen-printed in this way with multicolor-designs is usually pre-cut before heat application in case of a thermoadhesive film, and cut out during application in case of HF-welding.
However, this screen-printing method presents some drawbacks, in particular a low washing fastness of the printed colors which are losing their brightness after several washings of the decorated substrate, as well as a low abrasion resistance of the rayon-viscose flock-fibers, mostly when being wet. Also the screen-printing of the flock-layer requires the deposit of an important amount of printing-ink in order to cover the full length of the fibers, which in its turn also requires the use of screens with open mesh, limiting therefore the accuracy of the printing and making impossible the reproduction in four colors and halftones, like for instance photographic works.
In order to obtain a HF-weldable multicolor flocked-film, the use of another method is known where different pre-died nylon flock-fibers are applied by “multicolor-flocking”, color by color, each fiber/color going through separate screens and being fixed onto a HF-weldable film, each screen being made according the position of each color in the final multicolor design to be printed on the film. However, this method requires the use of one separate screen for each printed color, and for each printed design, which makes this production of flocked sheets slow and technically difficult, and consequently expensive.
SUMMARY OF THE INVENTION
The present invention tends to remedy all above listed drawbacks by a new fully-automatic method of continuous printing of multicolor designs onto a thermoadhesive or HF-weldable film, allowing the reproduction of the finest possible details, including reproduction of four color and halftone photographic artworks, the final printing of the flock-fibers being of high washing-fastness and high abrasion-resistance.
In this purpose, the object of the present invention is a method for automatic continuous printing of multicolor designs on a thermoadhesive or HF-weldable flocked film, characterized by the fact that it comprises the steps consisting in:
applying an thermoadhesive or HF-weldable film onto a strippable protection paper.
applying an adhesive layer onto said film,
flocking white colored fibers or flocks onto the adhesive layer,
preparing a pre-printed paper with multicolor-designs constituted by sublimable color agents able to vaporize and fix themselves permanently on the said fibers, those pre-printed designs being exactly a reverse image of the designs to obtain on the flocked film,
transferring the multicolor-designs by sublimation from said pre-printed paper onto a laminate made of the protection paper and of the flocked film by contact under selected pressure and temperature.
The use of this strippable protection paper allows continuous printing of the thermoadhesive or HF-weldable flocked film without modifying this film's integrity and cohesion.
In a first embodiment, the temporary protection paper is coated or covered by co-extrusion with a film of synthetic polymers which are HF-weldable, such polymers being for instance resins of poly-vinyl-chloride (PVC), which can be used under compact form or foamed by use of chemical or mechanical swelling agents.
In a second embodiment, the temporary protection paper is coated or covered by co-extrusion with a film of synthetic resins which are thermoadhesive, such as hot-melt resins made with co-polyesters, co-polyamides, or resins of acrylic-esters, synthetic latexes, ethylene-vinylacetate (EVA), etc.
The fibers used for the flocking operation will advantageously be synthetic fibers, preferably fibers made from polyamide, such as nylon 6 or nylon 6—6 (trademark from DU-PONT DE NEMOURS), or even more preferably fibers made from polyester. For instance, fibers used will be fibers going from 0.5 mm (0.9 Dtex) to 2 mm (6 Dtex) or even longer.
Those fibers can also be either man-made-fibers, such as rayon-viscose, either natural fibers, such as cotton, which will be previously treated in order to be able to fix the sublimable dyes.
According to another characteristic, the transfer operation is made by means of a heat-printing calender, ensuring a uniform pressure generally lower than 40 kPa, between the pre-printed paper and the laminate, and a temperature comprised between about 180° C. (350° F.) and 230° C. (450° F.), during approximately 5 to 45 seconds.
Advantageously, the pre-printed paper is produced by printing the sublimable dyes onto the paper by means of an ink-jet printer, assisted by a computer system.
This is an important part of the present invention, as a direct printing of a flocked film is made very difficult with an ink-jet printer, the reason being the small amount of ink sprayed by such ink-jet printers which are unable to cover and fill totally the flock-layer in one run.
According to the present invention, the sublimable dyes are printed onto the paper by the ink-jet printer in one pass, which allows high-quality printing of any type of designs, including four color and halftone jobs, the use of an ink-jet printer with computer assistance being free of any printing tools, such as screens, engraved cylinders or plates.
An other object of the present invention is a flocked film, thermoadhesive or HF-weldable, obtained directly by the metho
Crispino Richard
Lorengo J. A.
Societe d'Enduction et de Flockage
Young & Thompson
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